The Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to predefined policies, and to reconfigure it to respond to faults, load, and changes. To make matters even more difficult, current networks are also vertically integrated: the control and data planes are bundled together. Software-defined networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network's control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns, introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper, we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound application programming interfaces (APIs), network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms—with a focus on aspects such as resiliency, scalability, performance, security, and dependability—as well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined environment.

https://publications.uni.lu/bitstream/10993/20596/1/survey_on_SDN.pdf

Software-Defined Networking: A Comprehensive Survey

Software-Defined Networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network's control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound APIs, network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms -- with a focus on aspects such as resiliency, scalability, performance, security and dependability -- as well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined environment.

We describe the design and implementation of Open vSwitch, a multi-layer, open source virtual switch for all major hypervisor platforms. Open vSwitch was designed de novo for networking in virtual environments, resulting in major design departures from traditional software switching architectures. We detail the advanced flow classification and caching techniques that Open vSwitch uses to optimize its operations and conserve hypervisor resources. We evaluate Open vSwitch performance, drawing from our deployment experiences over the past seven years of using and improving Open vSwitch.

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The design and implementation of open vSwitch

We present the design, implementation, and evaluation of CONGA, a network-based distributed congestion-aware load balancing mechanism for datacenters. CONGA exploits recent trends including the use of regular Clos topologies and overlays for network virtualization. It splits TCP flows into flowlets, estimates real-time congestion on fabric paths, and allocates flowlets to paths based on feedback from remote switches. This enables CONGA to efficiently balance load and seamlessly handle asymmetry, without requiring any TCP modifications. CONGA has been implemented in custom ASICs as part of a new datacenter fabric. In testbed experiments, CONGA has 5x better flow completion times than ECMP even with a single link failure and achieves 2-8x better throughput than MPTCP in Incast scenarios. Further, the Price of Anarchy for CONGA is provably small in Leaf-Spine topologies; hence CONGA is nearly as effective as a centralized scheduler while being able to react to congestion in microseconds. Our main thesis is that datacenter fabric load balancing is best done in the network, and requires global schemes such as CONGA to handle asymmetry.

/pdf/conga-distributed-congestion-aware-load-balancing-for-3c0czbo3yn.pdf

CONGA: distributed congestion-aware load balancing for datacenters

A method for implementing a general packet radio service (GPRS) tunnel protocol (GTP) in a packet core (PC) of a third generation (3G) network having a split architecture where a control plane of the PC of the 3G network is in a cloud computing system, the cloud computing system including a controller, the controller to execute a plurality of control plane modules, the control plane to communicate with the data plane of the PC through a control plane protocol, the data plane implemented in a plurality of network elements of the 3G network by configuring switches implementing a data plane of the SGSN and GGSN and intermediate switches to establish a first and second GTP tunnel endpoint.

Implementing a 3g packet core in a cloud computer with openflow data and control planes

Multi-tenant datacenters represent an extremely challenging networking environment. Tenants want the ability to migrate unmodified workloads from their enterprise networks to service provider datacenters, retaining the same networking configurations of their home network. The service providers must meet these needs without operator intervention while preserving their own operational flexibility and efficiency. Traditional networking approaches have failed to meet these tenant and provider requirements. Responding to this need, we present the design and implementation of a network virtualization solution for multi-tenant datacenters.

/pdf/network-virtualization-in-multi-tenant-datacenters-t0dk1uiqgo.pdf

Network virtualization in multi-tenant datacenters

In general, the present invention relates to a virtual platform in which one or more distributed virtual switches can be created for use in virtual networking. According to some aspects, the distributed virtual switch according to the invention provides the ability for virtual and physical machines to more readily, securely, and efficiently communicate with each other even if they are not located on the same physical host and/or in the same subnet or VLAN. According other aspects, the distributed virtual switches of the invention can support integration with traditional IP networks and support sophisticated IP technologies including NAT functionality, stateful firewalling, and notifying the IP network of workload migration. According to further aspects, the virtual platform of the invention creates one or more distributed virtual switches which may be allocated to a tenant, application, or other entity requiring isolation and/or independent configuration state. According to still further aspects, the virtual platform of the invention manages and/or uses VLAN or tunnels (e.g, GRE) to create a distributed virtual switch for a network while working with existing switches and routers in the network. The present invention finds utility in both enterprise networks, datacenters and other facilities.

Method and apparatus for implementing and managing virtual switches

For a network that includes several managed edge switching elements and several managed non-edge switching elements that are for implementing a logical switching element, some embodiments provide a method of distributing packet processing across the several managed non-edge switching elements. The method receives a packet for processing through the logical switching element. Based on a determination that the packet needs to be processed by a managed non-edge switching element, the method determines a particular managed non-edge switching element of the several managed non-edge switching elements to forward the packet. The method forwards the packet to the particular managed non-edge switching element for the particular managed non-edge switching element to process the packet.

Method and apparatus for robust packet distribution among hierarchical managed switching elements

Some embodiments provide a method that processes network data through a network. The method receives a packet destined for a network host associated with a logical datapath set implemented by a set of managed edge switching elements and a set of managed non-edge switching elements in the network. The method determines whether the packet is a known packet. When the packet is a known packet, the method forwards the packet to a managed switching element in the set of managed edge switching elements for forwarding to the network host. When the packet is not a known packet, the method forwards the packet to a managed switching element in the set of managed non-edge switching elements for further processing.

Packet processing for logical datapath sets

Some embodiments provide a method for managing several managed switching elements in a network. The method determines configurations for the several managed switching elements to implement a first logical data path set. Based on the determined configurations, the method configures a first set of the several managed switching elements to implement the first logical data path set. The method configures a second set of the several managed switching elements to implement a second logical data path set.

Paul S. Ingram

Papers

Network virtualization in multi-tenant datacenters

Method and apparatus for implementing and managing virtual switches

Method and apparatus for robust packet distribution among hierarchical managed switching elements

Packet processing for logical datapath sets

Hierarchical managed switch architecture